L-carnitine, a major component of red meat, may increase an individual’s susceptibility to cardiovascular disease, such as atherosclerosis, and adverse cardiac events, such as stroke and myocardial infarction.

Red meat is a major source of L-carnitine, which is metabolized to the pro-atherogenic agent trimethylamine-N-oxide (TMAO) by bacteria in the small intestine. This study examined the relationship between the consumption of dietary L-carnitine and atherosclerosis risk. Researchers measured the serum concentrations of L-carnitine in 2595 human subjects undergoing cardiac evaluation and in mice fed with either choline, carnitine, or TMAO supplements.

Researchers discovered that the risk of developing cardiovascular diseases, such as atherosclerosis, and suffering from adverse cardiac events, such as stroke and myocardiac infarction, was high in human subjects and animals with plasma levels of L-carnitine and TMAO. The findings of this study support the hypothesis that regular ingestion of large quantities of red meat may increase cardiovascular morbidity and mortality risk , as well as promote the occurrence of adverse cardiac events.